Ideally you need to get your teeth professionally whitened or bleached to get a bright white set of dentition. but since because of COVID 19 situation, it cannot be done, u can try some easy home remedies. u mix some baking soda with lemon juice and brush your teeth with that. u can use glizer toothpaste or colgate visible white toothpaste also.
Next Steps
visit a dentist and get your teeth professionally whitened or bleached.
Health Tips
professional whitening should always be preceded by scaling polishng or oral prophylaxis.
Avoid tea, coffee , red wine and very spicy food that may produce stains.